The present invention relates to a mechanical food intake restriction device for the treatment of morbid obesity. More specifically, the invention relates to a mechanical food intake restriction device for surgical application in the abdomen of a patient for forming a stoma opening in the stomach or esophagus of the patient.
Mechanical food intake restriction devices in the form of gastric banding devices, in which a band encircles a portion of the stomach, have been used in surgery for morbid obesity to form a small gastric pouch above the band and a reduced stoma opening in the stomach. Although such a band is applied around the stomach to obtain an optimal stoma opening during surgery, some prior gastric banding devices are provided with an adjustment means enabling a minor post-operation adjustment of the size of the stoma opening. In all such prior art devices such as disclosed in U.S. Pat. No. 4,592,339, European Patent No. 0611561 and International Patent Application WO 94/27504, the adjustment means typically comprises an inflatable cavity in the band and an injection port in fluid connection with the inflatable cavity for adding fluid to or withdrawing fluid from the latter. In practice, the band is made of silicone rubber which is a material approved for implantation and the fluid is a liquid such as an isotonic salt solution.
It has been found, however, that the prior art bands may eventually dislocate downwardly on the stomach and there is an increased risk of stoma stenosis due to a small range of adjustment of the band. It has also been found that the volume of the gastric pouch above the band increases in size up to ten times after an operation. Therefore the pouch volume during surgery needs to be very small, approximately 7 ml. To enable the patient to feed the stomach with sufficient nutrition immediately after an operation considering such a small gastric pouch, the stoma initially needs to be relatively large and later needs to be substantially reduced, as the pouch volume increases. To be able to achieve a significant range of adjustment of the band, the cavity in the band has to be relatively large and is defined by a thin flexible wall, normally made of silicone material. Furthermore, the size of the stoma opening has to be gradually reduced during the first year after surgery as the gastric pouch increases in size. As indicated above, the reduction of the stoma opening using the prior art gastric banding devices is achieved by adding liquid to the cavity of the band via an injection port to expand the band radially inwardly.
A great disadvantage of repeatedly injecting liquid via the injection port is the increased risk of the patient getting an infection in the body area surrounding the injection port. If such an infection occurs the injection port has to be surgically removed from the patient. Moreover, such an infection might be spread along the tube interconnecting the injection port and the band to the stomach causing even more serious complications. Thus, the stomach might be infected where it is in contact with the band, which might result in the band migrating through the wall of the stomach. Also, it is uncomfortable for the patient when the necessary, often many, post-operation adjustments of the stoma opening are carried out using an injection needle penetrating the skin of the patient into the injection port.
Further it may happen that the patient swallows pieces of food too large to pass through the restricted stoma opening. If that occurs the patient has to visit a doctor who can remove the food pieces, if the band design so permits, by withdrawing some liquid from the band to enlarge the stoma opening to allow the food pieces to pass the stoma. Then, the doctor has to add liquid to the band in order to regain the restricted stoma opening. Again, these measures require the use of an injection needle penetrating the skin of the patient, which is uncomfortable for the patient.
Another problem with known adjustable gastric banding devices is that the isotonic salt solution can diffuse from the inflatable cavity of the band through the surrounding band walls of silicone rubber when there is a slight overpressure prevailing in the cavity. There is also a risk some time after the operation of liquid leakage from the injection port, from the tube between the latter and the band, and from the band itself. Most critical is the inflatable balloon cavity.
According to the invention a mechanical food intake restriction device is provided in which the risk of liquid leaking from the device is substantially reduced or eliminated. The invention provides an adjustable mechanical food intake restriction device which does not require the use of an injection needle for accomplishing post-operation adjustments of the stoma opening, and provides an adjustable mechanical food intake restriction device which permits post-operation adjustments that are comfortable for the patient.
In accordance with the invention a mechanical food intake restriction device is provided for surgical application in the abdomen of a patient for forming a stoma opening in the stomach or esophagus of the patient. The device includes an elongated restriction means, a forming means for forming the restriction member into a substantially closed loop around the stomach or esophagus, the loop defining a restriction stoma opening, and a post-operation non-invasive adjustment device for mechanically adjusting the restriction member to change the size of the restriction opening. As a result, there is no liquid directly involved in the elongated restriction member itself for providing inflation thereof, enabling post-operation adjustments of the device of the invention to change the stoma opening of the patient. The adjustment device may be incorporated in the restriction member as well as being controlled by a hydraulic device. The expression "post-operation non-invasive adjustment device" means that the adjustment device is capable of adjusting the restriction member after the operation without the need for invasive measures, such as penetration of the skin for example by injection needles or surgery, or by any other means that penetrate the skin. Though an injection port could be used in embodiments using a hydraulic device, the port preferably would be for enabling a single, once and for all, calibration of the amount of liquid contained by the hydraulic device.
In accordance with a preferred first adjustment principle, the adjustment device adjusts the longitudinal extension of the elongated restriction member in a loop form.
In a preferred embodiment of the invention utilizing the first adjustment principle, the restriction member comprises a main portion and two elongated end portions, and the adjustment device establishes longitudinal relative displacement between the end portions of the restriction member, so that the size of the restriction opening is adjusted. The forming means may comprise any suitable known or conventional device capable of practicing the desired function, such as a spring material forming the elongated restriction member into the loop, so that the restriction opening has a predetermined size, and the adjustment device may adjust the restriction member against the spring action of the spring material. In other words, the restriction member may comprise a spring clip. The spring material may be integrated in the restriction member.
Preferably, the adjustment device comprises a movement transferring member, suitably a drive wheel, in engagement with at least one of the end portions of the restriction member and operable to displace the one end portion relative to the other end portion of the restriction member. The drive wheel may advantageously be in engagement with both of the end portions of the restriction member and be operable to displace the end portions relative to each other. An elongated flexible drive shaft may be operatively connected to the drive wheel, for transferring manual or motor generated power from a location remote from the restriction member. In its simplest embodiment, the drive wheel may comprise a pulley in frictional engagement with the restriction member. As an alternative, a gear rack may be formed on at least one of the end portions of the restriction member and the drive wheel may comprise a gear wheel in mesh with the gear rack. Other suitable known or conventional mechanisms may also or alternatively be used as the adjustment device.
The movement transferring member may alternatively comprise at least one cylinder and a piston, which is movable therein and is connected to one of the end portions of the restriction member, the piston being operable to longitudinally displace the one end portion of the restriction member relative to the other end portion of the restriction member. Alternatively, the movement transferring member may comprise two interconnected cylinders and two pistons in the respective cylinders connected to the end portions, respectively, of the restriction member, the pistons being operable to longitudinally displace the end portions of the restriction member relative to each other. Other known or conventional devices also or alternatively can be used as the movement transferring member.
A motor, which is fixed relative to the main portion of the restriction member and has a rotating drive shaft operatively connected to the movement transferring member, may be positioned relative to the elongated restriction member such that the drive shaft extends transverse thereto. Alternatively, the motor may be positioned relative to the elongated restriction member such that the drive shaft extends substantially tangentially to the loop of the restriction member.
In another embodiment of the invention utilizing the first adjustment principle, the elongated restriction member is longitudinally resilient and the adjustment device comprises a contraction element adapted to longitudinally contract the resilient restriction member. Preferably, the elongated restriction member comprises a substantially nonresilient main portion and an end portion forming an elongated helical spring, which is contractable by the contraction element. The contraction element may suitably comprise an elongated flexible pulling member connected to the main portion of the restriction member and extending through the helical spring to contract the helical spring against an arresting member, which is fixed relative to the main portion of the restriction member. The pulling member may extend in an elongated tube joined at one end thereof to an arresting member, so that a motor remote from the restriction member may be attached to the other end of the elongated tube and pull the pulling member through the tube to contract the helical spring.
In yet another embodiment of the invention utilizing the first adjustment principle, the elongated restriction member comprises an elongated helical spring having a free end, and a body to which the spring is nonrotatably secured at its opposite end. The adjustment device rotates the helical spring in one direction to enlarge the coils of the helical spring to longitudinally contract the spring and to rotate the spring in the opposite direction to reduce the size of the coils of the spring to longitudinally extend the spring. As a preferred alternative, the restriction member comprises a further elongated helical spring having a free end and nonrotatably secured to the body at its opposite end, and the adjustment device comprises a drive shaft having two opposite end portions connected to the springs, respectively, at their free ends, the helical coils forming left and right hand helices, respectively. The adjustment device may alternatively comprise gearing having an input shaft and two opposite aligned output shafts connected to the helical springs, respectively, at their free ends, the input shaft being connected to the output shafts so that the output shafts rotate in the opposite directions upon rotation of the input shaft, the helical coils forming the same helices.
In accordance with a second adjustment principle, the adjustment device mechanically adjusts the restriction member so that at least a portion of a radially innermost circumferential confinement surface formed by the restriction member in the loop of the restriction member is substantially radially displaced in the loop.
In one embodiment of the invention utilizing a second adjustment principle, the restriction member comprises an elongated voltage responsive element forming part of the confinement surface and capable of bending into a bow in response to a voltage applied across the element, the radius of curvature of the bow being adjustable by changing the level of the voltage.
In another embodiment of the invention utilizing the second adjustment principle, the adjustment device changes the diameter of an elastic annular element of the restriction member, which forms the confinement surface. Preferably, the forming means comprises a substantially rigid outer annular element coaxially surrounding the elastic annular element, and the adjustment device comprises a device which pulls the elastic annular element radially outwardly towards the outer annular element to expand the elastic annular element. For example, the pulling device may comprise a plurality of threads secured to the elastic annular element along the circumference thereof and running from the elastic annular element via guide members attached to the outer annular element.
In yet another embodiment of the invention utilizing the second adjustment principle, the forming means comprises a substantially rigid outer annular element, and the restriction member comprises an elongated helical spring extending internally along the outer annular element and contacting the latter. The helical spring forms part of the circumferential confinement surface and has a free end. The restriction member further comprises a body to which the spring is nonrotatably secured at its opposite end. The adjustment device is adapted to rotate the helical spring in one direction to enlarge the coils of the spring to contract the circumferential confinement surface and to rotate the spring in the opposite direction to reduce the size of the coils of the spring to expand the circumferential confinement surface. As an alternative, which is preferred, the restriction member comprises two elongated helical springs forming part of the circumferential confinement surface and connected to the body of the restriction member. The adjustment device rotates each spring in one direction to enlarge the coils of the spring to contract the circumferential confinement surface and to rotate the spring in the opposite direction to reduce the size of the coils of the spring to expand the circumferential confinement surface.
In accordance with a third adjustment principle, the restriction member comprises at least two separate elements, at least one of which is pivoted so that it may turn in a plane in which the loop of the restriction member extends, and the adjustment device turns the pivoted element to change the size of the restriction opening. Preferably, the restriction member comprises a plurality of separate pivoted elements disposed in series, each pivoted element being turnable in the plane, and the adjustment device turns all of the pivoted elements to change the size of the restriction opening. For example, the pivoted elements may comprise lamellae arranged like the conventional adjustable aperture mechanism of a camera.
In accordance with a fourth adjustment principle, the adjustment device folds at least two foldable frame elements of the restriction member towards each other. Preferably, the foldable frame elements comprise two substantially semi-circular frame elements which are hinged together so that the semi-circular elements are swingable relative to each other from a fully open state in which they form a circle to a fully folded state in which they form a semi-circle.
In accordance with a fifth adjustment principle, the adjustment device turns the restriction member around a longitudinal extension thereof, the elongated restriction member being elastic and varying in thickness as seen in a cross-section therethrough. Suitably, the elongated restriction member comprises an elastic belt.
In all of the above-described embodiments of the invention the adjustment device is conveniently operated by any suitable motor, preferably an electric motor, which may be fixed directly to or be placed in association with the restriction member, or alternatively may be located remote from the restriction member, advantageously in the abdomen or subcutaneously. In the latter alternative the motor is advantageously connected to the adjustment device by a flexible power transmission conduit to permit suitable positioning of the motor in the abdomen of the patient. The motor may be manually activatable, for example by an implanted switch.
In some of the above described embodiments of the invention, however, the adjustment device may conveniently be operable by a hydraulic device, which preferably is manually activatable. The hydraulic device may advantageously include hydraulic servo means to facilitate manual activation. As an alternative, the hydraulic device may be powered by an electric motor, which may be manually activatable or controlled by a remote control device. The components of such a hydraulic device may be placed in association with the restriction member and/or be located at a suitable place in the abdomen or subcutaneously.
More specifically, a reservoir may be provided containing a predetermined amount of fluid for supplying the hydraulic device with hydraulic fluid. The reservoir defines a chamber for the predetermined amount of fluid and the hydraulic device changes the size of the chamber. The hydraulic device may comprise first and second wall portions of the reservoir, which are displaceable relative to each other to change the size of the chamber of the reservoir. The first and second wall portions of the reservoir may be displaceable relative to each other by manual manipulation thereof, preferably to permit manual pushing, pulling or rotation of any of the wall portions in one direction. Alternatively, the wall portions may be displaceable relative to each other by magnetic means (such as a permanent magnet and magnetic material reed switch, or other known or conventional magnetic devices), hydraulic means, or electric control means such as an electric motor. The magnetic means, hydraulic means, or electrical control means may all be activated by manual manipulation, preferably using a subcutaneously located manually manipulatable device. This control may be indirect, for example via a switch.
The hydraulic device may be adapted to operate the adjustment device with fluid from the reservoir in response to a predetermined first displacement of the first wall portion of the reservoir relative to the second wall portion of the reservoir, to increase the size of the restriction opening, and to operate the adjustment device with fluid from the reservoir in response to a predetermined second displacement of the first wall portion of the reservoir relative to the second wall portion of the reservoir, to decrease the size of the restriction opening. In this embodiment, no pump is used, only the volume of the reservoir is varied. This is of great advantage compared to the solution described below when a pump is used to pump fluid between the reservoir and the adjustment device because there is no need for a non-return valve and it is still possible to have fluid going both to and from the reservoir.
As an alternative, the hydraulic device may comprise an activatable pump for pumping fluid between the reservoir and the adjustment device. The pump may pump fluid both to and away from the adjustment device, or hydraulic means controlling the adjustment device. A mechanical manual solution is proposed in which it is possible to pump in both directions just by pushing an activating member in one direction. Another alternative is a pump pumping in only one direction and an adjustable valve to change the direction of fluid to either increase or decrease the amount of fluid in the reservoir. This valve may be manipulated manually, mechanically, electrically, magnetically, or hydraulically. Any kind of motor could of course be used for all the different operations as well as wireless remote solutions. The pump may comprise a first activation member for activating the pump to pump fluid from the reservoir to the adjustment device, and a second activation member for activating the pump to pump fluid from the adjustment device to the reservoir. The activation members may be operable by manual manipulation, preferably to permit manual pushing, pulling, or rotating thereof in one direction. Suitably, at least one of the activation members operates when subjected to an external pressure exceeding a predetermined magnitude.
Alternatively, at least one of the first and second activating members may be operable by magnetic means, hydraulic means, or electric control means such as an electric motor. The magnetic means, hydraulic means, or electrical control means may all be activated by manual manipulating means preferably located subcutaneously. This activation may be indirect, for example via a switch.
Advantageously, especially when manual manipulation means are used, a servo means system could be used. With servo means less force is needed for controlling the adjustment device. Hydraulic means is preferably used with servo means. One example is a closed system that controls another closed system in which the hydraulic means of the adjustment device is incorporated. Minor changes in the amount of fluid in a reservoir of the first system could then lead to major changes in the amount of fluid in a reservoir in the second system. In consequence, the change of volume in the reservoir of the second system affects the hydraulic means of the adjustment device, which is incorporated in the second closed system. The great advantage of this servo system is that the larger volume system could be placed inside the abdomen where there is more space and it still would be possible to use manual manipulation means of the smaller system subcutaneously. The servo reservoir could control the reservoir of the larger volume. The servo reservoir could be controlled directly or indirectly by a fluid supply means. The fluid supply means may be a small reservoir, which may be placed subcutaneously and may be activated by manual manipulation means controlling the servo reservoir.
Preferably, the servo means comprises hydraulic means and a servo reservoir and eventually a fluid supply reservoir. Both reservoirs define a chamber containing servo fluid, and the hydraulic device comprises first and second wall portions of the servo reservoir, which are displaceable relative to each other to change the size of the chamber of the servo reservoir. The hydraulic device may control the adjustment device indirectly, e.g. via an increased amount of fluid in the servo reservoir, in response to a predetermined first displacement of the first wall portion of any of the reservoirs relative to the second wall portion of the servo reservoir to decrease the size of the restriction opening, and to control the adjustment device in response to a second displacement of the first wall portion of any reservoir relative to the second wall portion, to indirectly increase the size of the restriction opening. The wall portions of the servo reservoirs may be designed to be displaceable relative to each other by manual manipulation thereof or be displaceable relative to each other by manually pushing, pulling or rotating any of the wall portions of the servo reservoir in one direction. Alternatively, the wall portions of the servo reservoir or fluid supply and reservoir may be displaceable relative to each other by magnetic means, hydraulic means or electric control means including an electric motor.
The magnetic means, hydraulic means, or electrical control means may all be activated by manually manipulated means preferably located subcutaneously. This control may be indirect for example via a switch.
Even in the broadest embodiment of the invention the adjustment device may comprise a servo means. The servo means may comprise a hydraulic operation means, an electric control means, a magnetic means, mechanical means or a manual manipulating means. The hydraulic operation means, electric control means, mechanical means or magnetic means may be activated by manual manipulating means. Using a servo system will save the use of force when adjusting the adjustment device which may be of importance in many applications, for example when a battery cannot put out enough current although the total energy in the battery is more than enough to power the system.
All solutions may be controlled by a wireless remote control means. Preferably, the remote control means comprises a motor for operating the adjustment device and an energizer for providing energy, and a signal receiving means comprises a control unit for powering the motor with energy provided by an energizer unit in response to a signal received from a signal transmitting means. Any known or to be developed remote control system may be used for this purpose.
The energizer unit may comprise a power supply that could be rechargeable, and the control unit powers the motor with energy from the power supply. Preferably, the power supply is an electric power supply such as a battery, and the motor is an electrical motor. In this case, the battery also continuously powers the circuitry of the signal receiving means between the adjustment operations, in order to keep the signal receiving means prepared for receiving signals transmitted from the transmitting means.
The motor may be any type of motor, such as pneumatic, hydraulic or electric motor and the energizer unit may be adapted to power the motor with pressured gas or liquid, or electrical energy, depending on the type of motor. Of course, in case the motor is an electrical motor, it may power pneumatic or hydraulic equipment.
Advantageously, the signal transmitting means transmits electromagnetic wave signals and the energizer draws radiant energy from the electromagnetic wave signals as they are transmitted to the signal receiving means and transfers the radiant energy into electric energy for powering an electric motor. The energizer unit may comprise a rechargeable electric power supply, such as a capacitor for storing the electric energy and the control unit may be in the rechargeable electric power supply in response to signals received from the signal transmitting means.
The energizer unit may draw radiant energy from the electromagnetic wave signals received by the signal receiving means and as they are transmitted, and transfer the radiant energy into electric energy for powering the motor. This is only practicable, however, if the adjustment device is of a type that requires little power for its operation, because in practice the electromagnetic wave signals transmitted in this connection often are of low power. Advantageously in an initial charging step the rechargeable power supply can be charged during a period of time without powering the electric motor. In a following step, when the power supply has been charged with sufficient energy, the control unit powers the electric motor with energy from the charged power supply to operate the adjustment device, direct or indirect, so that a desired change of the patient's stoma opening is achieved. If the capacity of the power supply is insufficient to achieve the necessary adjustment in one single operating step, the above steps may be repeated until the desired adjustment is achieved. Both these solutions are particularly simple and do not require any recurrent invasive measures for exchanging empty power supplies, such as batteries, that are required in an earlier described solution.
As an alternative, the energizer unit may comprise a battery, and/or an electrically operable switch to connect the battery to the signal receiving means in an on mode when the switch is powered and to keep the battery disconnected from the signal receiving means in a standby mode when the switch is unpowered, and a rechargeable electric power supply for powering the switch. The control unit may power the electric motor with energy from the battery in response to signals received from the signal transmitting means, when the switch is in its on mode. Suitably, the energizer unit may transfer the radiant energy into a current for charging the rechargeable electric power supply such as a capacitor. This solution is suited for adjustment devices of the type that require relatively high power for operation and has the advantage that the electronic circuitry of the signal receiving means does not have to be powered by the battery between adjustment operations, as described above in connection with the embodiment in which only a battery is used for powering the motor in response to signals to the signal receiving means. As a result, the lifetime of the battery can be substantially prolonged.
The energizer unit may comprise a coil connected to the signal receiving means for inducing an alternating current as electromagnetic wave signals are transmitted through said coil to the signal receiving means and a rectifier for rectifying the alternating current. The rectified current is used for charging the rechargeable power source, for instance a capacitor.
As should be realized by a skilled person, in many of the above-described embodiments of the invention the adjustment device may be operated by a control device, or manually manipulated device implanted under the skin of the patient, such as a pump, an electrical switch, or a mechanical movement transferring device. In the manual embodiment it is not necessary to use a motor for operating the adjustment device.
In embodiments including hydraulic transmission means, an injection port connected to the hydraulic means may be provided for enabling, normally single, once-and-for-all, calibration of the amount of fluid in the hydraulic system.
The invention also comprises a method comprising (a) surgically implanting in the abdomen of a patient with morbid obesity a mechanical food intake restriction device which forms a stoma opening in the stomach or esophagus, by forming an elongated non-inflatable restriction member (e.g. of bio-compatible material, or covered by bio-compatible material) into at least a substantially closed loop around the stomach or the esophagus of the patient, the loop defining a restriction opening; and then (b) when necessary for the patient's health or desired progress, in a non-invasive procedure mechanically adjusting the restriction member to change the size of the restriction opening. In this method, (a) may be practiced by implanting a restriction member comprising a main portion and two elongated end portions; and (b) may be practiced by establishing a longitudinal relative displacement between the end portions of the restriction member so that the size of the restriction opening is adjusted.
In the method, (a) may be practiced using laparoscopic techniques, such as shown generally in copending application Ser. No. 09/106,142 filed Jun. 29, 1998, the disclosure of which is incorporated by reference herein. For example, the method may be practiced by: (i) inflating the patient's abdomen with gas by penetration of the patient's skin, (ii) introducing at least one (e.g. two) laparoscopic trocars into the abdomen to introduce the elongated restriction member and one or more medical instruments, and then (iii) forming the elongated restriction member into the at least substantially closed loop.
Also, in practicing the method of the invention, (a) may be practiced by implanting a restriction member having a radially innermost circumferential confinement surface formed in the loop; and wherein (b) is practiced by causing at least a portion of the confinement surface to be radially displaced in the loop.
The invention may also comprise a surgical method for implanting a non-inflatable food restriction device for forming a stoma opening in the stomach or esophagus comprising: (a) Insufflating the abdomen of a patient to form a pneumoperitoneum. (b) Introducing at least one laparoscopic trocar into the abdomen. (c) Using a dissecting tool inserted through the laparoscopic trocar, dissecting the region of the esophagus or stomach preferably above the bursa omentalis. (d) Introducing the non-inflatable food restriction device in the abdomen and applying the device in at least a substantially closed loop around the stomach or esophagus. And, (e) post-operatively adjusting the restriction opening in a non-invasive procedure.
It is the primary object of the present invention to provide an advantageous yet relatively simple assembly and method for treating morbid obesity in a substantially non-invasive manner after initial surgical implantation of a non-inflatable restriction member. This and other objects will become clear from the detailed description and from the appended claims.